1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly, to a structure for positioning a sheet storing portion when the sheet storing portion is mounted on an image forming apparatus body.
2. Description of the Related Art
In the past, in an image forming apparatus, such as a copying machine or a printer, a sheet feeding device for supplying a sheet to an image forming portion is provided. The sheet feeding device includes a sheet feeding cassette that is mounted on an image forming apparatus body to store a sheet, and a feeding portion that feeds a sheet stored in the sheet feeding cassette. In a conventional image forming apparatus, a mounting direction of the sheet feeding cassette is a direction perpendicular to a sheet feeding direction. In the case of this apparatus, when the sheet feeding cassette is mounted within the image forming apparatus body, the mounting direction of the sheet feeding cassette is positioned by a positioning portion.
In the image forming apparatus, it is necessary to form an image at an appropriate position of a sheet in the image forming portion. Therefore, a position of an end in a width direction of the sheet stored in the sheet feeding cassette is matched with a position corresponding to a position of an end in a width direction of the image formed by the image forming portion, such that a position of the sheet in the width direction perpendicular to the sheet feeding direction is matched with the image. Therefore, the image can be formed in the image forming portion at an appropriate position in the width direction of the sheet fed from the sheet feeding cassette. However, the positions of the sheet feeding cassette and the image forming portion are shifted by a variation in dimensions of parts or a deformation of parts caused by an installation location of the image forming apparatus body. When the sheet feeding cassette and the image forming portion are mismatched in the width direction, the shift in the width direction occurs in the image formed on the sheet in the image forming portion.
Therefore, the conventional image forming apparatus is provided with a mechanism that adjusting the shift in the width direction of the sheet feeding cassette by the positioning portion with respect to the position of the image of the image forming portion. In this mechanism, the position of the sheet feeding cassette positioned by the positioning portion can be changed in the mounting direction of the sheet feeding cassette. For example, when the position of the sheet feeding cassette is changed by the positioning portion, first, the sheet feeding cassette is positioned by catching a hook provided in the sheet feeding cassette by a hook latch provided in the image forming apparatus body. Then, the position in the mounting direction of the sheet feeding cassette is adjusted by changing the position of the hook hatch through a ration of an adjusting screw attached to the image forming apparatus body (see Japanese Patent Laid-Open No. 2003-300635).
However, the positioning of the sheet feeding cassette in the conventional image forming apparatus is a stepless positioning because the sheet feeding cassette is positioned by rotating the adjusting screw. Therefore, the adjusting screw is rotated excessively or insufficiently by an operator, and the position adjustment in the mounting direction of the sheet feeding cassette cannot be performed easily and reliably.